Method of manufacturing wires from compacted metal tapes



June'l3, 1967 w. LUITEN ETAL METHOD OF MANUFACTURING WIRES FROM COMPACTED METAL TAPES Filed March 7, 1966 IN WILLEM LUITEN VENTOR PETER T.J.BEX BY AGENT Patented June 13, 1967 iiice 3,326,541 METHGD OF MANUFACTURING WERES FROM COMPACTED METAL TAPES Willem Luiteu and Peter Theodorus Joseph Ben, Em-

masingel, Eindhoven, Netherlands, assignors to North American ihillips Company, linen, New York, N.Y., a corporation of Delaware Filed Mar. 7, 1966, Ser. No. 532,442 Claims priority, application Netherlands, Mar. 12, 1965, 6,503,141 3 Claims. (Cl. 29-4205) ABSTRACT OF THE DISCLOSURE The present invention relates to a method of fabricating metal wire from metal powder in which the powder by means of flat rollers forms a self-supporting metal wire strip which further takes the form of a laminated structure. In addition, the laminated stack of metal wires may be enveloped and the entire assembly reduced to the desired thickness.

The term wire is to be understood to mean herein not only normal wire products of circular sectional area but also wire-shaped products of other profiles, for example of oval or polygonal sectional areas. The term metal powder is to denote not only powder of a single metal but also is to include powder of metal alloys, mixtures of different metal powders suitable for being converted into an alloy during or after the wire is formed, and powder of metal in conjunction with a restricted quantity, usually not more than about by weight, of powdery, inorganic metal compounds, such as carbides and oxides, which may be desired for obtaining given properties of the final product, for example, an improved wear resistance or creep strength.

From the techniques of powder metallurgy methods have been known for a long time in which metal powders are worked up by compression and sintering to a coherent body, the density of which is subsequently improved by kneading processes, for example forging, rolling and drawing. However, these methods do not permit of manufacturing continuously Wire or tape of metal powder.

During the last decade methods have become known in which metal powder can be worked up by rolling in a continuous process to band or wire.

It is then necessary to obtain by the very first rolling process a product from the powder which has satisfactory coherence so that it is self-supporting and the density, which is still insufiicient after the first rolling process, for example 60% of the theoretical density, can be considerably raised by further continuous kneading processing, whilst, in addition, the homogeneity can be improved where powder mixtures form the starting material.

It is known that in the manufacture of metal strips from powder rollers of a diameter more than 50 times and frequently more than 100 times the thickness of the strip to be made have to be employed in order to obtain a satisfactory coherence between the powder particles, in accordance with the shape of the grains, the granular size and the distribution according to granular size. In order to obtain strips of satisfactory density further rolling processes are required, the thickness of the metal strip being considerably further reduced, for example to about one-fifth or even to one-tenth.

It will be obvious that in this manner rollers of suitable diameter, for example of about half a metre are capable of providing only a very thin band, for example having a thickness of about 0.5 mm. However, the manufacture of tape of satisfactory density with a thickness of a few millimetres would require the use of rollers of a diameter of a few metres.

Such requirements have to be met by rollers for the manufacture of wire from powder, in which case many further complications are involved, for example considerable difliculties in the lateral control of the powder supply and the non-uniform pressure distribution owing to the variation in thickness from the centre to the sides of the Wire in its cross section.

It will be obvious that the use of very large rollers for the manufacture of wire of a thickness of 1 mm. or a few millimetres involves appreciable difiiculties. Moreover, profiled rollers required for the formation of the desired wire profile from powder are subjected to strong wear and cannot be repaired in the same simple manner as the flat rollers, which are worn off to a considerably lesser extent and which are used for densifying powder to strips.

According to the invention these disadvantages are obviated by densifying, in known manner, the metal powder with the aid of fiat rollers to form a self-supporting strip, the density of which being improved, if desired, with the aid of heating by further rolling, after which the strip thus obtained is worked up to a wire-shaped unit of laminated structure, which is machined by kneading to wire of the desired thickness.

An advantage of this method is that the conversion of powder into self-supporting tape may be performed with the aid of fiat rollers instead of profiled rollers, which are required for the direct manufactuer of wire from powder.

A further advantage is that the final thickness of the tape is not subjected to requirements with respect to the thickness of the tape. It is therefore possible to perform r the initial powder concentration by means of rollers of reasonable diameters, for example a diameter about 10 times smaller than in the case of direct manufacture of wire.

Part of the kneading process required for obtaining a satisfactory material density may be performed during the process of working the laminated intermediate product to the wire of the finally desired thickness.

For example, a nickel powder (granular size 50 to 200 is rolled between fiat rollers of diameters of 200 mm. with a gap between the rollers of 1.9 mm. to form a tape of a width of 50 mm. and a thickness of 2 mm., which is rolled in five steps to a thickness of 0.2 mm. with intermediate annealing processes in an atmosphere of nitrogen and 25% of hydrogen at 800 C.

In a similar manner tapes of copper, iron, nickel-iron and chromium-nickel alloy powder may be manufactured.

The tape obtained from the metal powder may be united to a wire-shaped assembly of laminated structure in many ways.

As is shown in a cross sectional view in FIG. 1 of the drawing, like in the manufacture of cigarettes, where the paper is folded in the form of a cylinder around the tobacco, a tape 2 of suitable width is wound cylindrically around a narrow metal strip 1 and this process is repeated with a number of further tapes 3, 4, 5 and so on until a wire-shaped assembly of a diameter of for example 5 mm. is obtained. The diameter is subsequently reduced by drawing to about 3 mm., the result being a compact, homogeneous wire.

In the manner shown in FIG. 2, fifteen strips 11 of a width of 3 mm. and a thickness of 0.2 mm. may be stacked and the assembly may be Wrapped up by folding in a tape 12 of a width of 16 mm. The resultant, enveloped stacks are subsequently rolled to a wire of a square profile with a thickness of 2 mm.

It is also possible to roll up the metal tape in the direction of its width. If desired further substances, for

example powderous substances, may be rolled up in layers together with the metal tape.

What is claimed is: '1. A method of manufacturing metal wire from metal powder comprising rolling said powder with flat rollers.

4 powder as claimed in claim 1 wherein strips of metal tape are stacked, and folding another metal tape about said stack to form an enveloped structure having a rectangular cross-section.

References Cited UNITED STATES PATENTS 3,095,283 6/1963 Wheeler 29-1916 FOREIGN PATENTS 16,211 11/1915 Great Britain.

CARL D. QUARFORTH, Primary Examiner.

A. J. STEINER, Assistant Examiner. 

1. A METHOD OF MANUFACTURING METAL WIRE FROM METAL POWDER COMPRISING ROLLING SAID POWDER WITH FLAT ROLLERS TO FORM A SELF-SUPPORTING METAL TAPE, FURTHER ROLLING SAID TAPE TO MAKE SAID TAPE DENSER, FORMING A LAMINATED WIRESHAPED ASSEMBLY OF A PLURALITY OF METAL TAPES, AND KNEADING SAID WIRE-SHAPED ASSEMBLY TO THE DESIRED THICKNESS. 